Automatic telephone call box



P 20, 1932- P. G. T. DE VILLIERS 1,878,762

AUTOMATIC TELEPHONE CALL BOX Filed Feb. 21. 1950 2 Sheets-Sheet 1 mum I W3 Gm 3 Jim do (1 0% bi hm V W Sept. 20, 1932.

P. T. DE VILLIERS 1,878,762

AUTOMATIC TELEPHONE CALL BOX Filed Feb. 21, 1930 2 Sheets-Sheet 2 m z ZWhwb-W 5, 67% BMXmW Wm Patented Sept. 20, 1932 r P GFFEE PETER eYsBnR'r THOMAS 'nn vrLLIEns, on rnnronm, TRANSVAAL, Un on or sorr'rn AFRICA, ASSIGNOR or ONE-HALF r MESSR-S. ROGERSPJENKINS & co. (rm L'rn,

OF DURIBAN, NATAL, UNION OF SOUTH AFRICA, A COMPANY UNION OF SOUTH AFRICA f AUTOMATIC 'rELErHonnoALL BOX Application filed February 21, 1930, Serial No. 430,240, and in Union of South Africa October 4, 1929.

This invention relates to improvements in an automatic telephone call boxand has for its object to provide a device which switches and controls telephone calls from public call offices in automatic telephone areas.

Certain improvements in automatic telephone call boxes have been described in my British Patent No. 162,639, and reference is,

"therefore, made to these specifications in or- 1' der to' make clear the present lnventlon.

The present invention may be adapted for use'in connection with a standard automatic telephone dial to which is suitably coupled a'mechanism for the purpose of our invention. The nut and lock-nut attached to the back of the shaft of automatic telephone dials at present in use is utilized in thisinvention to engage in acorresponding socket in the nature of a box spanner attached with a flexible joint to a main spindle in our mechanism or alternatively the back of the shaft or any other moving part of the dial can be coupled to such mainspindle in any known manner.

To'this spindle a pawl is fitted in any known manner to operate a ratchet wheel, causing it to movein an anti-clockwise direction through a partial revolution, when the dial is turned in a clockwise direction. The

' pawl'm'ay be so adapted as to cause the wheel to move forward afixed number of teeth for each movement of the dial, depending on the size and nature of the wheel and its teeth. When the dial has been operated a certain number of times, say nine times, then the pawl and ratchet wheel reach a position in relation to each other where no teeth are provided on the ratchet wheel and the mechanism is thus put out of operation,-thereby preventing unnecessary strain on a spring member disposed behind the ratchet wheel for thepurpose of bringing it back to its normal position. The ratchet wheel is kept in position by a holding pawl connected with r and controlled in any known manner by the switch arm of the telephone handset. Upon replacing the telephone handset after use the holding pawl is released, thus enabling the springmember under compression to bring the ratchet wheel backto its normal position.

In lieu of the ratchet wheel a toothed bar serted in the call box,'the contacts operated or rack may conveniently be employed, the only difference being that the pawl on-the main spindle will now move the rack in a horizontal or any required linear direction.

On the same spindle as the ratchet wheel is mounted a, cam on which a bead-or the like insulator travels, governing electric contacts of the automatic arrangement. Adjacent the first cam a second cam of different form is mounted on the spindle. A magnet of any type but preferable a permanent'magnet for the simplification of'the mechanism is disposed on the second cam. As the ratchet is rotated this second camrotates pernnttmg the magnet to drop under its own weight or alternatively to be drawndown by a spring member or in some other suitable manner and taking up a final position after a fixed number of movements preferably fourof the dlal, so that a trip bell-crank lever (describedin my British Patent No. 162,689) adh-eresto the magnet when operated by a coin.

This trip in its usual position short circuits the telephone transmitter acting as a shunt across the transmitter terminals so that speech on the call side is only possible after the coin has been inserted and the short circuit broken. If less than four or the specified number of digits isdialledand the coin inby the first cam on the ratchet wheel shaft connects the contact screw of the trip lever Figure 2 is a section on A B of Figure 1;

Figure 3 shows details of the electric contacts operated by the first cam;

Figure 4 is a section on C-D of Figure 1 omitting the partsshown in Figure 2; j Figure 5 is a diagram of the connections.

-tacts of the dial,rand'25 the contacts operated Referring to these drawings wherein like reference numbers indicate the same parts wherever occurring throughout all the views, 1 indicates the mainspindle, to which is =attachedthe'shaftofthe standard dial which in the embodiment illustrated in the accomxpanying drawingsengages a socket of box spanner form 2 by means of flexible coupling 3. On the shaft is further mounted the pawl 4 which engages the teeth on ratchet 5 when spindle 1 is rotated by the operation of the dial. 7 7

On shaft 6 of ratchet 5 is also mounted cam 7 adjacent theratchet wheel on to which bead 5 or insulator 8 bears down. To this bead is attached common spring 'contact 8a of the electric circuit. This spring contact has contact points 9 and 10 respectively to closethe electric circuits at ll and 12 respectively on r rotation 'of cam 7. a s

e If lessthan fourfigures are dialled in an 'embodiment-in'which cam-'Z'is so adjusted 1 "that four figures must be dialled beforecon- -"versation can proceed the contacts 9 and 11 will-remain' closed, so that if a coinis -in- "serted'at 13 it lifts the bell crank trip lever "-14 momentarily 'on its way down enablingthe' "exchange-operator to'hear the buzz between .theco'ntact screw 15*and vibratorcontact 16.

}A second camv 17 adjacent cam 7 also :imounted on shaft 6 permits the magnet 18 which is disposedon-cam 17 to drop to its new position indicated by dotted lines at 19 after ;-four numbers orthe specifiednumber of dig -it's have been dialled so thatwhen thecoin is -inserted"at '13itstr-ikes the trip lever let on its way down which then: swings over and adheres to' the magnet; thus breaking the shunt across'vibrator 16 and lead ifrom'the s Q contact 1:2,- thus allowing: conversation to *proceed. f

' The telephone switch arm is designated 20:

and operates the holding pawl 21 0n;rat'chet -=5 *whenllthe" handset is removed from atheiswitch arm =hook. 3 Stops 22 limit -:the ,position-Of theBratchet- 5' andspiral spring 23 bringsthematchet back to its original'position when-pawl 21 isldisengagedo Referringto Figure 5,24 indicates the conby the switch arm 20. 2 Receiver terminals are i shown at .26 "and transmitter terminals at 27. i The 're'st of the circuit diagram is the :usual" diagramxfor an automatic telephonecall box.

l In operationpthevnumberrequired is dialled "after removingathe telephone handset fromswitch arm. If the number is one offourdigits :Lthe ratchet wheel moves forward through a distance of'8 teeth, (if 2teeth are Ltaken when-one figure of the number I is- -z.di alled). the magnet 18 takes up its new position 19, permittingthe trip lever '14 to adhere i to it wheniit-he coin is inserted. Also contacts 10v and 121willbeclosed, due to thebead S-being now on the raised portion of cam 7.-

spindle :for operating said ratchetwheel, a

ClIIlT fiXGd-OH saidsecondaryjspindle for operating transmitted contacts, second: cam on said secondaryspindle, a bar magnetspivoted to said-casing:andresting in-:engage-. v

ment with said secondcam.

i 2.1An. automatieitelephone call boX-of; the

type having a casing and operated'byastandard automatic impulse dial on ashafaamain spindle coupledtosaid iiial shaft, 24 secondvaryspindle on saidqcasingcarrying a fixed ratchet-wheel and a spring detent co-operat-v ingtherewith=and actuatedby the switchiarm, a pawl on themain spindle for operating said ratchet wheel,- a camfixed on 'saids'sec ondary spin'dle for pperating transmitter contacts, second .cam:ionsaidsecondary spindle,- abar magnet pivoted to said casing and restingin engagement withsaidse'cond cam-,and a bell crank-trip lever pivoted: at

the junction of its two armseto saidcasingin such a Positionthat'one endthereof projects into'said coin chute'and-isthereby tripped by the falling call coin to a positionito be attracted land held bysaid barv magnet.

. i 1 "R 3. An automatic telephone call-box of the type having a casing and operated byza 1standardautomaticf impulse dial on a shaft,

a fmain spindle coupled to said dial shaft', a secondary. spindle =.-on said casing carry- 1 ing a fixed ratchet wheel and a spring detent co-operatingtherewith, a pawl on; the main spindle for operating said ratchet wheel; a

cam fixed on said secondary spindle for op er ratingtransinitter contacts, a second cam -on;.;

said secondary spindle, a. bar ,magnet, pivaot'ed. to saidscasing and resting inengagement with said. second cam, and a bell crank trip lever pivoted-at theijunction of its twoarms to said casing in such a position that -OI1 eEtl."- l'Il'.-L-.12O I projects into said coin chute ini the \pathrof the inserted call coin, while the other arm in its normal positionicontacts with a vibrator contact completing thereby the short circuit 1 across. the transmitter terminals,=.r-

whichshort circuit is opened by thetripping ofsaidbell crank leverby the passage of the inserted :call coin" down the coin chute.

- 4. An automatic telephonecall box of'the type having a casing andioperated by 21 standard automatic impulse dial on a shaft, a main spindle coupled to said dial shaft, a secondary spindle on said casing carrying a fixed ratchet wheel and a spring detent cooperating therewith, a pawl on the main spindle for operating said ratchet wheel a cam fixed on said secondary spindle for operating transmitter contacts, a second cam on said secondary spindle, a bar magnet piv- 10 oted to said casing and resting in engagement with said second cam, and a bell crank trip lever pivoted to said casing and adapted to be tripped by a call-coin inserted in the coin chute, to a position to be attracted and held 1 by said bar magnet, said bar magnet being adapted to be progressively caused to move to a position to attract and hold the outer arm of said bell crank trip lever after a predetermined number of digits have been dialled and said bellcrank lever is tripped by the inserted call coin.

Signed at Johannesburg, South Africa, this 14th day of January A. D. 1930.

PETER GYSBERT THOMAS de VILLIERS. 

